BD437S

Overview

The BD437S is an NPN silicon epitaxial-base power transistor manufactured by onsemi. It is housed in a TO-225 (TO-92) plastic package with three pins for through-hole mounting. Key electrical specifications include a maximum DC collector current of 4 A, a collector-emitter voltage rating of 45 V, and a collector-base voltage of 45 V. The device features a maximum power dissipation of 36 W, a minimum DC current gain of 30, and a transition frequency of 1 MHz. It operates at temperatures up to 150°C.

Feature Summary

• Designed as a complementary silicon power transistor suitable for medium-power linear and switching applications.

Applications

• Medium power linear circuits
• Switching applications

Procurement Notes

Verify the specific suffix 'S' against official datasheets to confirm package variations or compliance status. Ensure compatibility with thermal management requirements given the 36W dissipation rating. Confirm RoHS compliance documentation availability prior to integration into final assemblies.

Selection Notes

Select this component for designs requiring high current handling in a compact TO-225 package. Consider the 45V voltage rating and 4A current capacity when sizing heat sinks. Verify that the 1MHz transition frequency meets the speed requirements of the intended switching or linear application.

Part Context

The BD437S belongs to the BD437 series of complementary NPN/PNP silicon power transistors. This family is engineered for robust performance in general-purpose power applications. The S suffix typically denotes a specific tape-and-reel or packaging variant within the standard TO-225 outline.

Replacement Considerations

Complementary PNP types are BD434, BD436, and BD438 respectively. Direct substitutes should match the 4A current, 45V voltage, and TO-225 package constraints.